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The suspect, Sean Andrew Duncan,had a pattern of suspicious behavior, according to an affidavit

Duncan tried to destroy a memory chip and thumb drive when FBI agents raided his home

(CNN)An FBI raid in Sterling, Virginia, on Friday night was part of an investigation into a man who allegedly supported ISIS, according to an FBI affidavit obtained by CNN affiliate WJLA.

During the raid, the suspect, Sean Andrew Duncan, attempted to destroy evidence, the criminal complaint, which WJLA obtained from the FBI, alleges.

When agents arrived at Duncan's home on Friday, he "ran out the back door, barefoot, and with something in his hand," the affidavit alleges. Duncan then threw "a plastic baggie" over their heads, which, when recovered, was found to contain "a memory chip stored within a thumb drive that had been snapped into pieces, and placed in a liquid substance that produced frothy white bubbles."

Duncan had recently traveled to Turkey with his wife, but was deported to the United States, according to the affidavit. In December 2017, a detained ISIS recruiter showed the FBI a list of handwritten names and phone numbers, which contained Duncan's information, the document alleges.

According to the affidavit, authorities searched Duncan's cell phone over the summer and found "numerous internet searches for ISIS-related materials," including information on ISIS attacks, weapons, body armor, surveillance and defense tactics, and paintball venues.

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Efforts to reach Duncan or a representative of his for comment over the weekend were unsuccessful.

The affidavit alleges an unnamed co-conspirator told the FBI in July 2017 that Duncan had connected with her on social media and expressed an interest in joining ISIS and conducting a terrorist attack in the United States; he also asked her to travel to Syria with him and his wife, but she declined, the document says.

In August 2017, an undercover FBI employee identified an encrypted messaging account associated with Duncan and, posing as a co-conspirator, used the account to ask Duncan if he had any connections in Syria, the affidavit alleges; Duncan answered, "No a couple have been marytred (sic)," the document says.